You summon my superior SNACK solutions. Are you thinking an embedded drawer? If the slot is tight enough, you might be able to just put a normal SNACK drawer in there no problem.
I could look into making a version of these feet that have latching divots and a corresponding slightly larger drawer slide that could fit into the whole expansion card space, allowing it to still be used as a normal expansion card storage slot.
Alternatively, I haven’t touched it in a while, but I had previously developed a Tall SNACK Drawer that when used in pairs, could lift the back of the laptop up off a surface. I decided to not sell them since the tiny locking lugs for expansion cards weren’t holding the drawer frames in place well enough. I could maybe give that one another look.